Sheet conveyor apparatus and method

ABSTRACT

An improved sheet slowdown method and apparatus includes gripping a leading end portion of a sheet with clamp assemblies of a main conveyor and transporting the sheet along a horizontal path to a transfer station which is located directly above a pile of sheets. At the transfer station, the leading end portion of the sheet is engaged by clamp assemblies of a slowdown conveyor which is operating at the same speed as the main conveyor. The clamp assemblies of the main conveyor are then released and the speed of operation of the slowdown conveyor is reduced to decelerate the sheet before it is released at a receiving station where the leading end portion of the sheet engages a stop member to position the sheet relative to the pile of sheets. This reduction in the speed of operation of the slowdown conveyor may be provided by actuating a differential gear mechanism to provide relative rotation between an input member connected to a constant speed source of power and an output member which is drivingly connected to the slowdown conveyor.

11mm States Patent 1 91 Norton 1 May 1, i973 1541 SHEET CONVEYOR APPARATUS AND 3,109,644 11/1963 Reinartz ..271/68 METHOD Prima ExaminerEvon C. Blunk [75] Inventor' gap Norton Twmsburgh Assistziiit Examiner -Bruce H. Stoner, Jr.

10 Att0rney-Yount, Flynn & Tarolli [73] Assignee: Harris-Intertype Corporation,

Cleveland, Ohio [57] ABSTRACT [22] Filed: May 3, 1971 An improved sheet slowdown method and apparatus includes ri in a leadin end ortion of a sheet with [21] Appl' 139917 clamp ass er lzlie s of a main con eyor and transporting Related Application Data the sheet along a horizontal path to a transfer station which is located directly above a pile of sheets. At the Continuation of Sen 2|, i969, transfer station, the leading end portion of the sheet is abandoned' engaged by clamp assemblies of a slowdown conveyor which is operating at the same speed as the main con- [52] U.S. Cl ..271/76, 271/79 veyon The Clamp assemblies f the main Conveyor are [5 Int. Cl. then relea ed and the peed of peration of the lowof Search 77, 76, 78, down onveyor is reduced to decelerate the heet be- 271/75, 69, 63 fore it is released at a receiving station where the leading end portion of the sheet engages a stop member to References Cited position the sheet relative to the pile of sheets. This reduction in the speed of operation of the slowdown UNITED STATES PATENTS conveyor may be provided by actuating a differential 1,252,856 1/1918 Story ..271/79 gear mechanism to Provide relative rotation between 1,537,594 5/1925 Elsworth et a1 ..271/79 an input member connected to a constant speed 2,657,052 10/1953 Elliott ..271/79 source of power and an output member which is 2,130,841 9/1938 Eckhard-- drivingly connected to the slowdown conveyor. l,329,936 2/1920 Spiess ..271/79 2,836,418 5/1958 Blattner et al .271/68 37 Claims, 8 Drawing Figures PATENTED MY 1 3 SHEET 1 OF 3 INVENTOR. ROfiL-WT K. NORTON BY A 2/, g

PATENTED 3 3.7305517 SHEET 2 or 3 lily/V436 SHEET CONVEYOR APPARATUS AND METHOD This is a continuation of application Ser. No. 792,693, filed Jan. 2 l 1969, and now abandoned.

This invention relates generally to an apparatus and method for transporting sheet-like members and more particularly to an apparatus and method for transporting a sheet-like member at a relatively high speed and decelerating the sheet-like member before its engages a stop member at a receiving station.

During the manufacture of cartons and similar articles, large sheets of paper are cut into a number of smaller carton blanks. To facilitate handling, the carton blanks of each sheet are cut in such a manner as to leave narrow, relatively weak tabs or sections interconnecting the carton blanks to form a sheet or sheet-like member. After being suitably formed by processing through a cutting machine, each sheet of carton blanks is conveyed to a receiving station where the sheet is positioned on a stack of similar sheets by engagement with a stop member. In order to obtain the desired flow rate of sheets of carton blanks, a known conveying apparatus transports a sheet of carton blanks to a receiving station at a high speed and releases the sheet in such a manner as to bring the leading end portion of the sheet into abutting engagement with the stop member. However, the forces resulting from the high speed impact of the sheet against the stop member tends to break or rupture the tabs so that the carton blanks separate and are difficult to handle.

Accordingly, it is an object of this invention to provide a new and improved apparatus and method which enables a sheet or sheet-like article to be transported at a high speed to a receiving station and positioned on a stack of sheets without subjecting the sheet to relatively large impact forces.

Another object of this invention is to provide a new and improved method and apparatus for transporting a sheet or sheet-like article at a high speed to a receiving station and reducing the speed of the sheet before it engages a stop member for positioning the sheet at the receiving station.

Another object of this invention is to provide a new and improved apparatus for reducing the speed of a moving sheet or sheet-like article before it engages a stop member to position the sheet on a pile of sheets at a receiving station wherein the apparatus includes a slowdown conveyor assembly for grippingly engaging a leading end portion of a sheet while it is directly above the pile of sheets and is being moved under the influence of the main conveyor assembly and then reduc ing the speed of the sheet to a speed which is substantially below the speed at which the sheet is moved by the main conveyor assembly to thereby minimize the possibility of damage to the sheet when it engages the stop member.

Another object of this invention is to provide a new and improved apparatus in accordance with the next preceding paragraph wherein the apparatus further includes differential gear means for driving the slowdown conveyor assembly from a constant speed source, the differential gear means being selectively operable to vary the speed of operation of the slowdown conveyor means.

Another object of this invention is to provide a new and improved apparatus and method for transporting a sheet or a sheet-like member having a plurality of interconnected portions to a receiving station where the sheet is positioned in a predetermined orientation by engagement of a leading end portion of the sheet with a stop member, wherein the leading end portion of the sheet is engaged by a slowdown conveyor means and the speed of the sheet is continuously reduced to a speed substantially below the speed at which the sheet is transported by a main conveyor means and the sheet is released at such a speed that the leading end portion engages the stop member to arrest a forward movement of the sheet without rupturing the connections between the portions of the sheet.

These and other objects and features of the invention will become more apparent upon a consideration of the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a schematic illustration of a conveyor system which includes a slowdown conveyor assembly for receiving sheets traveling at a high speed from a main conveyor assembly, the main conveyor assembly being shown engaging a sheet at a pickup station;

FIG. 2 is a schematic illustration of the conveyor system of FIG. 1 illustrating the main conveyor assembly transporting the previously engaged sheet toward the slowdown conveyor assembly;

FIG. 3 is a schematic illustration of the conveyor system of FIG. 1, illustrating the transfer of the sheet from the main conveyor assembly to the slowdown conveyor assembly at a sheet transfer station;

FIG. 4 is a schematic illustration of the conveyor system of FIG. 1 depicting the relationship of the main conveyor assembly and slowdown conveyor assembly immediately after the sheet has been released at the receiving station by the slowdown conveyor assembly;

FIG. 5 is a schematic illustration of the operation of the slowdown conveyor assembly;

FIG. 6 is an enlarged schematic illustration of a differential gear assembly for driving the slowdown conveyor assembly;

FIG. 7 is a schematic illustration of a cam assembly for actuating the differential gear assembly of FIG. 6 to vary the speed of operation of the slowdown conveyor assembly; and

FIG. 8 is a schematic illustration of a clamp assembly on the main conveyor assembly and a clamp assembly on the slowdown conveyor assembly, the clamp assemblies being depicted at the transfer station whereat a sheet is being engaged at the same time by both of the clamp assemblies.

The present invention provides a conveyor system for transporting sheets or sheet-like members to a receiving station where they are positioned on a pile by engagement of leading end portions of the sheets with a stop member. The conveyor system includes a main conveyor assembly which grips the leading end portion of each of the sheets in turn and transports them along a substantially horizontal path at a relatively high speed to a transfer station which is over the pile. In order to prevent damaging the sheets by high speed impact against the stop member, a slowdown conveyor assembly grips the leading end portion of each of the sheets in turn at the transfer station while operating at the same speed as the main conveyor assembly. After the sheets have been released by the main conveyor assembly, the slowdown conveyor assembly continuously reduces the speed of the sheets before releasing them at the receiving station. In the illustrated embodiment of the invention, the speed of the slowdown conveyor assembly and each of the sheets is reduced to a speed substantially below the speed of the main conveyor assembly by operation of a differential gear assembly which drivingly connects a constant speed source of power with the slowdown conveyor assembly. A vacuum assembly is provided for applying suction to the trailing end portions of the sheets while their speed is being reduced by the slowdown conveyor assembly to thereby minimize any tendency of the sheets to bend or buckle.

Although a conveyor system (FIG. 1) can advantageously be used for transporting many different types of sheets and sheet-like articles, the conveyor system is illustrated in association with a cutting machine 12 for cutting relatively large sheets 14 into a plurality of carton blanks or portions. The carton blanks making up each sheet 14 are separated by elongated cuts or slits and are interconnected by relatively weak, narrow tabs or sections of uncut material between the carton blanks. By leaving the carton blanks interconnected in this manner, the handling of the carton blanks is facilitated since a number of the carton blanks are interconnected to form the sheets or sheet-like members 14. After the sheets 14 have been cut by operation of rollers 18, the sheets are transported to a receiving station where a stack or pile 22 of the sheets is accumulated on a known pile elevator 24. As each of the sheets 14 is deposited on the pile 22, a leading end portion 28 of the sheet is brought into engagement with a stop member 30 to position the sheet relative to the other sheets of the stack 22.

The cutting machine 12 is capable of high-speed operation to economically produce a relatively large number of carton blanks in a short time. In order to handle the relatively large number of sheets of carton blanks which issue from the cutting machine 12, the conveyor system 10 includes a main conveyor assembly 34 which is continuously operated at a high speed to quickly transport the sheets 14 from a pickup station 36 along a substantially horizontal path toward the receiving station 20. To this end, the main conveyor assembly 34 includesa plurality of grippers 38 which are interconnected in a known manner by a flexible drive chain 40 which is driven in an endless path around an idler sprocket 41 at a substantially constant speed by a drive sprocket 42.

As the grippers 38 are moved through the pickup station 36, they are operated to an open condition by a suitable cam 43. The leading end portion 28 of the sheets 14 enter the open grippers 38 as the sheets issue from the cutting machine 12. The grippers 38 are then released by the cam 43 to enable the grippers to engage the sheets 14. In FIG. 1 the gripper 38a is engaging the leading end portion 28 of the sheet 14a. Continued rotation of the drive sprocket 42 moves the sheet 14a forwardly at a high speed along a substantially horizon- I tal path toward the receiving station 20. This is illustrated in FIG. 2 where the sheet 14a is being transported toward the receiving station 20 by the main conveyor assembly 34.

As was previously explained, each sheet or sheet-like member 14 is made up of a plurality of carton blanks which are interconnected by relatively narrow, weak tabs of uncut material. Therefore, if the leading end portions 28 of sheets 14 are brought into engagement with a stop member 30 while traveling at the high speed at which they are transported by the main conveyor 34, the forces resulting from the impact of the sheets against the stop member 30 would tend to break or rupture the connections between the carton blanks. The various carton blanks would then slide around loosely on the pile 22 and make handling of the pile extremely difficult. To prevent this breaking or rupturing of the connections between the carton blanks, the speed of each of the sheets 14 is substantially reduced before the sheet is brought into engagement with the stop member 30.

The conveyor system 10 includes a slowdown conveyor assembly 44 which engages the leading end portions of the sheets 14 at a transfer station 46 which is directly above or over the pile 22. This is illustrated in FIG. 3 where the sheet 14a is being transferred from the main conveyor assembly 34 to the slowdown conveyor assembly 44. The slowdown conveyor assembly 44 then reduces the forward velocity or speed of the sheet 14a to a relatively low speed at which an impact of the leading end portion 28 of the sheet 14a with the stop member 30 will not break or rupture the connections between the carton blanks making up the sheet.

The extent to which the speed of the sheets 14 must be reduced by the slowdown conveyor assembly 44 to prevent a separation of the carton blanks, will depend upon the material from which the carton blanks are made and the strength of the connections between the carton blanks. However, a speed reduction of at least 10 to 1 is advantageous in order to provide the main conveyor assembly 34 with sufficient speed to handle the sheets as they are discharged from the cutting machine 12 while providing for an adequate speed reduction by the slowdown conveyor assembly 44 to prevent a separation of the carton blanks by engagement of the leading end portion 28 of a sheet with the stop member 30. By way of an example, in one embodiment of the invention, while handling a particular type of sheet, the main conveyor assembly 34 transports the sheets at a speed of approximately ninety-nine inches per second. The slowdown conveyor assembly 44 reduces the speed of the sheets to approximately four inches per second before releasing the sheets. However, it should be understood that the invention, in its broader aspects at least, is not to be limited to any particular speed reduction ratio or speeds of travel of the sheets.

The slowdown conveyor assembly 44 engages the leading end portions 28 of each of the sheets 14 directly over the pile at the transfer station 46 (see FIGS. 3 and 5) while the sheet is being moved at a relatively high speed along a substantially horizontal path by the main conveyor assembly 34. After the leading end portion of each of the sheets 14 has been released by an associated one of the clamp assemblies 38 of the main conveyor assembly 34, the slowdown conveyor assembly 44 continuously reduces the forward or downstream speed of the sheet as it moves along the horizontal path and then releases the sheet at the receiving station 20 (FIG. 4). To this end, the slowdown conveyor assembly 44 includes a plurality of grippers 50 which are interconnected by a flexible drive chain 54. The drive chain 54 is driven at varying speeds along a continuous path around an idler sprocket 56 by a drive sprocket 58.

To promote a smooth transfer of the sheets 14 between the main conveyor assembly 34 and slowdown conveyor assembly 44, as the grippers 50 of the slowdown conveyor assembly move through the transfer station 46 they travel at the same speed as do the grippers 38 of the main conveyor assembly. Thus, while the grippers 50a and 38a are moving horizontally through the transfer station 46 (FIGS. 3 and 5) at the same speed, the gripper 50a of the slowdown conveyor assembly 44 is opened by a cam 57 (FIG. 1) to engage the leading end portion 28 of the sheet 140. After the gripper 50a has been released by the cam 57, the gripper 38a of the main conveyor assembly 34 is opened by a cam 59 to release the sheet for movement under the influence of only the slowdown conveyor assembly 44.

Once the sheet 14a has been engaged by the slowdown conveyor assembly 44, the speed of operation of the slowdown conveyor assembly is reduced. This reduction in the speed of operation of the slowdown conveyor assembly 44 decelerates the gripper 50a and sheet 14a as the gripper 50a moves through a distance (FIG. 5) past a point where the gripper 50a is opened by a cam 61 and the sheet 14a is released (see FIGS. 1 and 4). The gripper 38a, which transported the sheet 14a to the transfer station 46, is moved at a substantially constant speed by operation of the main conveyor assembly 34. Therefore, the gripper 38a is ahead of the gripper 50a when the sheet 14a is released (see FIG. 4). It should be noted that the transfer of the sheet 14a from the main conveyor assembly 34 to the slowdown conveyor assembly 44 and the reduction in speed of the sheet occurred above and between leading and trailing ends 220 and 22b of the pile 22.

After operation of the slowdown conveyor assembly 44 has reduced the speed of the sheet 14a and the sheet is released by the gripper 50a (see FIG. 4), the sheet continues its forward movement until the leading end portion 28 of the sheet 14a engages the stop member 30 (in the manner illustrated in FIG. 2 for the preceding sheet 1412). This engagement of the leading end portion 28 of the sheet 14a with the stop member 30 positions the sheet 14a relative to the other sheets on the pile 22, and particularly relative to the preceding sheet 14b upon which the sheet 14a will lie.

While the speed of the sheet 14a and the speed of operation of the slowdown conveyor assembly 44 was being reduced to decelerate the sheet 14a, the gripper 38c of the main conveyor assembly 34 was engaging the leading end portion 28 of the next succeeding sheet 14c and moving this sheet toward the transfer station 46 at a relatively high speed (see FIG. 4). Due to the previously described deceleration of the sheet 14a, the sheet 14c may be moved into an overlapping relationship with the sheet 14a. This is schematically illustrated in FIG. 4 wherein the leading end portion 28 of sheet 140 has overtaken a trailing end portion 64 of the sheet 14a. To prevent interference between the sheets 14a and 140, the trailing end portion 64 of the sheet 14c is allowed to move downwardly to a position slightly below the substantially horizontal path of movement of the sheets 14a and 14c.

When the leading end portion 28 of the sheet 14c arrives-at the transfer station 46, the leading end portion of this sheet will be engaged by the next succeeding gripper 50c of the slowdown conveyor assembly 44 while the gripper 500 is traveling at the same speed as the gripper 380. Therefore, the speed of operation of the slowdown conveyor assembly 44 and the speed of the gripper 500 are increased from the relatively low speed at which the preceding sheet 14a was released by the gripper 50a to the relatively high speed of the gripper 380. Accordingly, the gripper 50c is accelerated to the speed of the gripper 380 while the gripper 500 is moved through the distance 62 (see FIG. 5) so that the grippers 38c and 500 are traveling beside each other at substantially the same speed when the sheet 14c is transferred from the gripper 380 to the gripper 50c. The sheet 140 is then decelerated by the slowdown conveyor assembly 44 and released at the receiving station 20. Of course, the previously described sequence of operation is repeated as long as sheets 14 issue from the cutting machine 12.

The sheets 14 are relatively flexible since they are made up of a plurality of carton blanks which are interconnected by relatively narrow or weak tabs or sections of uncut material. When the forward speed of these sheets is reduced by the operation of the slowdown conveyor assembly 44, the sheets tend to bend or buckle due to a tendency of the trailing end portions 64 (see FIG. 1) of the sheets to overrun or move forwardly faster than the leading end portions 28. Since this buckling of the sheets could result in a breaking of the connections between the carton blanks making up the sheets, a vacuum assembly 68 is provided for applying suction to an underside of the trailing end portion 64 of each of the sheets, in the manner illustrated in connection with the sheet 14b in FIG. 1.

The vacuum assembly 68 includes a perforated drum 72 which is rotated about a sleeve 74 having a central chamber 76 which is connected to a source of low pressure or vacuum. The sleeve 74 has an elongated slot 80 which enables air to be drawn into the chamber 76 through holes or apertures 84 in the rotating drum 72 to thereby apply suction to the trailing end portions 64 of the sheets 14. The drum 72 is rotated in a clockwise direction, as viewed in FIG. 1, so that the peripheral surface of the drum is moving in the same direction and at the same speed as the trailing end portion 64 of the sheets 14 to thereby prevent a tearing of the sheets. Thus, the speed of rotation of the drum 72 is varied directly with the speed at which each of the sheets 14 is moved by the slowdown conveyor assembly 44.

When one of the sheets 14 is being moved at a relatively high speed past the vacuum assembly 68 by the main conveyor assembly 34, the application of suction to the sheet would unduly retard its forward motion and could result in a breaking or rupturing of the connections between the carton blanks making up the sheet. To prevent this from happening, a shield 88 is moved across the opening 80 in the sleeve 74 to block the passages 84 so that suction is not applied to the sheet 14 at this time. The shield 88 is moved away from the opening 80 only when the speed of a sheet is being reduced by the slowdown conveyor assembly 44 (see FIGS. 1-4). Although the shield 88 can be moved between the open position of FIG. 1 and closed position of FIGS. 2-4 by many different types of driven in conjunction with the slowdown conveyor assembly 44.

From the foregoing description, it can be seen thatthe grippers 50 of the slowdown conveyor assembly 44 are first moved at a constant, relatively high speed, while one of the grippers is passing through the transfer station 46. The speed of the grippers 50 is then reduced until a sheet is released at a relatively low speed. The grippers must then be quickly accelerated to the relatively high speed which the grippers 38 of the main conveyor assembly 34 are moved. To provide this varying speed, the slowdown conveyor assembly 44 is connected to a constant speed source of power, preferably the same source of power for driving the main conveyor assembly 34, by a gear train 96 (see FIG. 6) which is operable to provide the requisite variation in the speed of operation of the slowdown conveyor assembly.

Although many different types of drives can be used to provide the variation in the speed of operation of the slowdown conveyor assembly 44, the preferred embodiment of the gear train 96 includes a differential gear assembly 98. The differential gear assembly 98 is selectively actuated by a suitable control means, in the present instance a cam assembly 102, to enable relative rotation to occur between an input shaft 106 connected to the constant speed source of power and an output shaft 108 which is connected to the drive sprocket 58 of the slowdown conveyor assembly 44. Upon rotation of the input shaft 106 in the direction of the arrow in FIG. 6, a gear 112 drives an input gear 114 to rotate a side gear 116 of the differential gear assembly 98 in the direction indicated by the arrow. When one of the grippers 50 is moving through the transfer station 46, there is no differentiation by the differential gear assembly 98. At that time the opposite side gear 118 of the differential gear assembly is driven by the pinion gears 122 and 124 which remain stationary on a pinion shaft 126 of a carrier or spider 128 as the carrier or spider and pinion gears are rotated about the central axis of a transversely extending support shaft 132 of the spider 128 by the rotation of the side gear 1 l6. Rotation of the side gear 118 rotates an output gear 136 to drive gears 138 and 140, the shaft 108, and the drive sprocket 58 of the slowdown conveyor assembly 44 at a substantially constant speed.

As soon as the gripper 50 has passed through the transfer station 46 and into the deceleration area 60 (see FIG. the cam assembly 102 (FIG. 6) causes the differential gear assembly 98 to differentiate and thereby decelerate the drive shaft 108 and the drive sprocket 58 of the slowdown conveyor assembly 44. To provide for this differentiation, the support shaft 132 is rotated in the direction of the arrow 144 by the cam assembly 102 to rotate the spider 128 and pinion gears 122 and 124 to thereby reduce the speed of rotation of the side gear 118 relative to the side gear 116 in a known manner. The support shaft 132 is rotated at a substantially constant rate in the direction of the arrow 144 by the cam assembly 102, until the speed of the grippers 50 and the sheet 14 has been reduced to a relatively low speed at which the leading end portion 28 of the sheet can be brought into engagement with the stop member 30 without breaking or rupturing the connection between the carton blanks making up the sheet.

After a sheet 14 has been released by one of the grip pers 50, the next succeeding gripper 50 must be accelerated to the speed of the main conveyor assembly 34. To this end, the cam assembly 102 rotates the support shaft 132 in the opposite direction, that is, in the direction of the arrow 148 of FIG. 6, to cause the dif ferential gear assembly 98 to differentiate in the opposite direction. This differentiation moves the pinion gears 122 and 124 in such a manner as to accelerate the side gear 118 and increase the rate of rotation of the drive shaft 108. In this manner, the grippers 50 are quickly brought up to the same speed as at which the grippers 38 are moved by the main conveyor assembly 34. Once a gripper 50 has reached the transfer station 46, at substantially the same time as does one of the grippers 38 and a sheet 14, differentiation of the differential gear assembly is stopped and the speed of movement of the gripper 50 is maintained substantially constant in the manner previously explained.

To effect the previously described actuation of the differential gear assembly 98, the cam assembly 102 includes a cam 154 which cooperates with a follower 158 connected to the support shaft 132 of the spider 128 (FIG. 6). The cam 154 (FIG. 7) includes a constant diameter surface portion 160 along which a roller 164 of the follower 158 moves while the gripper 50 is moving through the transfer station 46. As soon as the gripper 50 reaches the end of the transfer station 46, the roller 164 engages a deceleration surface portion 168 which constantly increases in distance from a center drive shaft 170 for the cam 154 to pivot the follower 158 and support shaft 132 in the direction of the arrow 144 in FIG. 6. As was previously explained, this pivoting movement of the shaft 132 causes the differential gear assembly 98 to differentiate and slow down the drive shaft 108.

After the sheet 14 has been released for the gripper 50, the roller 164 engages a relatively short acceleration surface portion 174 of the cam 154. The acceleration portion 174 enables the roller 164 to move radially inwardly, that is, toward the center of the cam 154, to pivot the follower assembly 158 and support shaft 132 in the direction of the arrow 148 of FIG. 6. As was previously explained, this rotation of the support shaft 132 causes the differential gear assembly 98 to differentiate in such a manner as to accelerate the drive shaft 108. The acceleration portion 174 of the cam 154 ends at the substantially constant radius portion 160 which engages the roller 164 while the gripper 50 moves to the transfer station 46.

Although it is contemplated that many different types of grippers 38 and 50 can be used in association with the main and slowdown conveyor assemblies 34 and 44, the grippers advantageously take the form of respective clamp assemblies and 192 (see FIG. 8). The clamp assembly 190 is connected to the chain 40 of the main conveyor assembly 44 and includes a post portion 196 having an operating surface 198 against which an upper surface of the sheet 14 is pressed by an operating surface 202 of a finger 204. A biasing spring (not shown) resiliently urges the finger 204 inwardly to the closed or clamping position illustrated in FIG. 8. While the clamp assembly 190 is passing through the pickup station 36, the cam 59 rocks an actuator bar or shaft 210 against the influence of the biasing spring and closes the finger 204 against the sheet in a known manner. A spring 206 enables relative movement to occur between the finger 204 and post 196 once a sheet 14 has been engaged between the operating surfaces 198 and 202. The clamp assembly is then moved toward the transfer station by a drive bar 214.

At the transfer station 46, the slowdown conveyor assembly 44 moves the clamp assembly 192 into operating alignment with the clamp assembly 190. When the clamp assembly 192 is so positioned, the cam 57 is effective to operate the clamp assembly to the open condition against the influence of a suitable biasing spring (not shown). An operating surface of a post portion 220 of the clamp assembly 192 is then in a position which is coplanar and aligned with the operating surface 198 of the post portion 196 of the clamp assembly 190. A finger 224 of the clamp assembly 192 is then moved to the illustrated closed position under the influence of the biasing spring (now shown). A spring 226 enables relative movement to occur between the finger 224 and post 220 once the sheet 14 has been clamped between them. It should be noted than an operating surface of the finger 224 of the clamp assembly 192 is then coplanar with the operating surface 202 of the finger 204 of the clamp assembly 190. This coplanar relationship between the operating surfaces of the fingers and posts of the clamp assemblies 190 and 192 results in the application of a minimum amount of stress to the sheet 14 while it is being engaged by the clamp assembly 192 and traveling forward under the influence of the clamp assembly 190.

Once the clamp assembly 192 has firmly engaged the sheet 14, the clamp assembly 190 is released by the cam 59. The sheet 14 can then be decelerated under the influence of the clamp assembly 192 and the slowdown conveyor 44. Although both clamp assemblies 190 and 192 have been illustrated with fixed post portions 196 and 220 adjacent to the upper surface of the sheet 14, it is contemplated that the post of one or both of the clamp assemblies could be made movable and positioned adjacent to the lower surface of the sheet. It should be noted that the actuator bar 210 and support bar 214 for the clamp assembly 190 are spaced somewhat ahead of the actuator bar 230 and support bar 232 for the clamp assembly 192. This spacing and positioning of the clamp assembly 190 in a leading relationship relative to the clamp assembly 192 enables the clamp assembly 192 to be decelerated without interferring with the clamp assembly 190.

To facilitate the transfer of the sheet 14 from the main conveyor assembly 34 to the slowdown conveyor assembly 44, the main conveyor assembly 34 includes a horizontal first or lower run or section 240 (FIG. 1) which is, for a portion of its length, transversely aligned or in a side-by-side relationship with a lower or first run 244 of the slowdown conveyor assembly 44. The main conveyor assembly 34 includes a second or upper run 246 which is positioned above a second or upper run 250 of the slowdown conveyor assembly 44 to enable the clamp assemblies 38 to move past the clamp assemblies 50 on the second or upper run 250 of the slowdown conveyor assembly 44. When the slowdown conveyor assembly 44 is positioned in the manner illustrated in FIG. 1, the main conveyor assembly 34 substantially circumscribes the slowdown conveyor assembly to provide a relatively compact conveyor system 10.

In view of the foregoing remarks, it can be seen that l have provided a conveyor system 10 which includes a main conveyor assembly 34 and slowdown conveyor assembly 44 for quickly transporting sheets 14 to a receiving station 20 and enabling the sheets to be positioned on a pile or stack of sheets 22 without subjecting the sheets to relatively large impact force when they engage a stop member 30 which positions the sheets at the receiving station. To this end, the main conveyor assembly 34 is operated at a relatively high constant speed to quickly transport each of the sheets 14 in turn to the transfer station 46 which is located above the pile 22. Once a sheet reaches the transfer station 46, the leading end portion 28 of the sheet is clampingly engaged by a gripper on the slowdown conveyor assembly 44. The differential gear assembly 98 is then actuated to reduce the speed of operation of the slowdown conveyor assembly 44 to a speed at which the leading end portion 28 of the sheet can be brought into engagement with the stop member 30 without damaging the sheet. The sheet is then released and the speed of operation of the slowdown conveyor assembly 44 is increased back to the constant, relatively high speed of the main conveyor assembly to enable a gripper 50 on the slowdown conveyor assembly to engage the next succeeding sheet.

Having described a specific preferred embodiment of the invention, the following is claimed:

1. A sheet slowdown mechanism for reducing the speed of a moving sheet-like member before it is deposited on a pile of sheet-like members at a receiving station where the sheet-like member is positioned on the pile by engagement of its leading end portion with a stop member, said mechanism comprising main conveyor means for transporting the sheet-like member to a transfer station which is located directly above the pile while grippingly engaging the leading end portion of the sheet-like member and for releasing the sheetlike member at the transfer station, said main conveyor means including first gripper means for engaging the leading end portion of the sheet-like member and first chain means for moving said first gripper means along a first endless path, and slowdown conveyor means for grippingly engaging the leading end portion of the sheet-like member over the pile at the transfer station while the sheet-like member is being moved under the influence of said main conveyor means, for reducing the speed of movement of the sheet-like member while transporting the sheetlike member away from the transfer station, and for releasing the leading end portion of the sheet-like member after reducing its speed to a speed substantially below the speed at which the sheet-like member is transported by said main conveyor means to thereby minimize the possibility of v damage to the sheet-like member when it engages the stop member, said slowdown conveyor meansincluding second gripper means for engaging the leading end portion of the sheet-like member at the transfer station and second chain means for moving said second gripper means along a second endless path.

2. A sheet slowdown mechanism as set forth in claim 1 wherein said first chain means includes first and second parallel runs of chain, and saidslowdown conveyor means includes means for supporting saidsecondgripper means for movement between said first and second runs of said first chain means.

3. A sheet slowdown mechanism as set forth in claim 1 further including means for retarding forward movement of a trailing end portion of the sheet-like member as said slowdown conveyor means reduces the speed of movement of the sheet-like member and means for rendering said means for retarding forward movement of the sheet-like member ineffective at times other than when the speed of the sheet-like member is being reduced by said slowdown conveyor means.

4. A sheet slowdown mechanism as set forth in claim 1 wherein said first gripper means includes clamp means for clampingly engaging opposite sides of the leading end portion of the sheet-like member and drive means for moving said clamp means along a horizontal path extending over the pile, and said second gripper means includes clamp means for clampingly engaging opposite sides of the leading end portion of the sheetlike member, drive means for moving said slowdown conveyor clamp means along the horizontal path at a speed which is equal to the speed at which the sheetlike member is moved by said main conveyor means when said slowdown conveyor clamp means is moving through the transfer station to thereby facilitate engagement of the leading edge portion of the sheetlike member while it is being moved by said main conveyor means, for reducing the speed of said slowdown conveyor clamp means while the slowdown conveyor clamp means is being moved along the horizontal path after the leading end portion of the sheet-like member has been engaged by said slowdown conveyor clamp means and said main conveyor means has released the leading end of the sheet-like member, and for accelerating the clamp means after the leading end portion of the sheet-like member has been released by said clamp means at the receiving station to thereby bring the speed of the clamp means back up to at least the speed at which the sheet-like member is transported by said main conveyor means.

5. A sheet slowdown mechanism as set forth in claim 4 wherein said drive means includes differential gear means for driving said slowdown conveyor means, said differential gear means including an input member operatively connected to a substantially constant speed source of power and an output member operatively connected to said slowdown conveyor means, said drive means further including means for operating said differential gear means to reduce the speed of said output member relative to the speed of said input member to thereby effect theaforesaid reduction in the speed of said clamp means for for operating said differential gear means to accelerate said output member relative to said input member to thereby effect the aforesaid acceleration of said clamp means.

6. A sheet slowdown mechanism as set forth in claim 1 wherein said first chain means includes first and second horizontal runs of chain disposed above the pile of sheets and extending from at least a trailing end portion of the pile of sheets to a leading end portion of the pile of sheets.

7. A sheet slowdown mechanism as set forth in claim 6 wherein said first gripper means includes a post portion and a finger portion for engaging the sheet-like member with an operating surface and pressing the sheet-like member against an operating surface of said post portion, and said second gripper means includes a post portion for engaging the sheet-like 'member and a finger portion for engaging the sheet-like member with an operating surface and pressing the sheet-like member against an operating surface of said post por-.

tion of said second gripper means, each of said operating surfaces of said second gripper means being substantially coplanar with one of said operating surfaces of said first gripper means when said second gripper means is initially brought into engagement with said sheet-like member at said transfer station to thereby minimize distortion of the sheet-like member.

8. A sheet slowdown mechanism as set forth in claim 6 wherein said slowdown conveyor means includes means for supporting said second chain means and said second gripper means for movement along a portion of the second path which extends between said first and second horizontal runs of chain.

9. A sheet slowdown mechanism as set forth in claim 1 further including vacuum means for applying suction to a trailing end portion of the sheet-like member as the speed of the sheet-like member is being reduced by said slowdown conveyor means to thereby tend to minimize buckling of the sheet-like member as its speed is reduced by said slowdown conveyor means.

10. An assembly comprising main conveyor means for transporting a sheet-like member to a transfer station, said main conveyor means including first clamp means operable from an open condition to a closed condition clampingly engaging the sheet-like member, first drive means for moving said first clamp means along a first endless path having a straight portion which extends through the transfer station, and first actuator means for operating said first clamp means from the closed condition to the open condition as said first clamp means moves along said straight portion of the first path, and slowdown conveyor means for receiving the sheet-like member from said main conveyor means at the transfer station and for reducing the speed of movement of the sheet-like member to a speed substantially below the speed at which the sheet-like member is transported by said main conveyor means and for the releasing the sheet-like member at a receiving station, said slowdown conveyor means including second clamp means operable from an open condition to a closed condition clampingly engaging the sheet-like member as it is moving through the transfer station along the straight portion of the first endless path under the influence of said main conveyor means, second drive means for moving said second clamp means along a second endless path having a straight portion which extends through the transfer station and is transversely adjacent and parallel to said straight portion of the first endless path which extends through the transfer station to thereby facilitate engagement of the sheet-like member by said second clamp means while the sheetlike member is being moved through said transfer station by said main conveyor means, and second actuator means for operating said second clamp means from the open condition to the closed condition as said second clamp means moves along said straight portion of said second path.

11. An assembly as set forth in claim wherein said second drive means includes an input member operatively connected with a source of power which drives said input member at a substantially constant speed, a rotatable output member drivingly connected with said second clamp means, and means for rotating said output member at a first rate so that said second clamp means is moved forwardly by said second drive means along said straight portion of the second endless path at a speed which is substantially the same as the speed at which said first clamp means is moved through said transfer station by said first drive means, for reducing the rate of rotation of said output member to a second rate which is substantially less than said first rate of rotation to thereby reduce the speed of forward movement of said second clamp means along said straight portion of said second endless path and the speed of movement of the sheet-like member before the sheetlike member is released at the receiving station, and for increasing the rate of rotation of said output member from said second rate to said first rate before said second clamp means engages another sheet-like member at the transfer station.

12. An assembly as set forth in claim 11 wherein said means for rotating said output member includes differential gear means for enabling relative rotation to occur between said output member and said input member.

13. An assembly as set forth in claim 12 wherein said 7 means for rotating said output member further includes cam means for actuating said differential gear means to effect relative rotation between said output member and said input member.

14. An assembly as set forth in claim 11 wherein said straight portions of said first and second endless paths extend beyond a leading end portion of the pile.

15. An assembly as set forth in claim 10 wherein said first clamp means includes a plurality of main gripper assemblies, said first drive means includes first flexible connector means for interconnecting and moving said main gripper assemblies along the first endless path, said second clamp means includes a plurality of slowdown gripper assemblies, and said second drive means includes second flexible connector means for interconnecting and moving said slowdown gripper assemblies along the second endless path which is circumscribed by the first endless path along which said main gripper assemblies are moved by said first drive means.

16. An assembly as set forth in claim 10, further including vacuum means for applying suction to a trailing end portion of the sheet-like member as the speed of the sheet-like member is being reduced by said slowdown conveyor means to thereby retard forward movement of the trailing end portion of the sheet-like member.

17. An assembly as set forth in claim 16 furtherincluding means for rendering said vacuum means ineffective for applying suction to the trailing end portion of the sheet-like member while the sheet-like member is moving under the influence of said main conveyor means.

18. An assembly for transporting a sheet-like member having a plurality of interconnected portions the sheet-like member at the transfer station, said main conveyor means including first gripper means for engaging a leading end portion of a sheet-like member and first drive means for moving said first gripper means along a first endless path a horizontal part of which extends through said transfer station, and slowdown conveyor means for continuously reducing the speed of the sheet-like member to a speed substantially below the speed at which the sheet-like member is transported by said main conveyor means after the leading end portion of the sheet-like member has moved through the pick-up station and releasing the sheet-like member at the receiving station while it is traveling at such a speed that the leading end portion engages the stop member to arrest forward movement of the sheet-like member without rupturing the connections between the portions of the sheet-like member, said slowdown conveyor means including second gripper means for engaging the leading end portion of the sheet-like member as it moves along the horizontal part of said first endless path at the transfer station while the sheet-like member is moving forward under the influence of the main conveyor means and second drive means for moving said second gripper means along a second endless path a horizontal part of which extends adjacent and parallel to said horizontal part of said first endless path, for decelerating said second gripper means-as it moves along the horizontal part of said second endless path and the sheet-like member engaged by the second gripper means from a relatively high speed at which said main conveyor means transported the sheet-like member to a relatively low speed at which the sheet-like member is released by said second gripper means at the receiving station, and for subsequently accelerating said second gripper means to the relatively high speed at which said main conveyor means transported the sheet-like member to enable said second gripper means to engage a next succeeding sheet-like member, said first gripper means including a plurality of main gripper assemblies, said first drive means including first flexible connector means for interconnecting and moving said main gripper assemblies along the endless path, said second gripper means including a plurality of slowdown gripper assemblies, and said second drive means including second flexible connector means for interconnecting and moving said slowdown gripper assemblies along an endless path which is circumscribed by the endless path along which said main gripper assemblies are moved by said first drive means.

19. An assembly as set forth in claim 18 further including means for retarding forward movement of a trailing end portion of the sheet-like member while the speed of the sheet-like member is being reduced by said slowdown conveyor means.

20. An assembly as set forth in claim 18 wherein said second drive means includes differential gear means for drivingly connecting a substantially constant speed source of power with said slowdown conveyor means and means for actuating said differential gear means to effect the deceleration and acceleration of said second gripper means.

21. An assembly as set forth in claim 18 further in.- cluding vacuum means for applying suction to a trailing end portion of the sheet-like member as the speed of the sheet-like member is being reduced by said slowdown conveyor means to thereby retard forward movement of the trailing end portion of the sheet-like member and minimize buckling of the sheet-like member, said vacuum means including a surface portion which engages the sheet-like member and is moved in the same direction as the sheet-like member to thereby minimize the possibility of rupturing connections between the portions of the sheet-like member due to the effect of said vacuum means.

22. An assembly for transporting a sheet-like member having a plurality of interconnected portions to a receiving station whereat the sheet-like member is positioned in a predetermined orientation by engagement of a leading end portion of the sheet-like member with a stop member, said assembly comprising main conveyor means for transporting the sheet-like member from a pickup station to a transfer station and releasing the sheet-like member at the transfer station, said main conveyor means including first gripper means for engaging a leading end portion of a sheet-like member and first drive means for moving said first gripper means along a first endless path a horizontal part of which extends through said transfer station, slowdown conveyor means for continuously reducing the speed of the sheet-like member to a speed substantially below the speed at which the sheet-like member is transported by said main conveyor means after the leading end portion of the sheet-like member has moved through the pick-up station and releasing the sheet-like member at the receiving station while it is traveling at such a speed that the leading end portion engages the stop member to arrest forward movement of the sheetlike member without rupturing the connections between the portions of the sheet-like member, said slowdown conveyor means including second gripper means for engaging the leading end portion of the sheet-like member as it moves along the horizontal part of said first endless path at the transfer station while the sheet-like member is moving forward under the in fluence of the main conveyor means and second drive means for moving said second gripper means along a second endless path a horizontal part of which extends adjacent and parallel to said horizontal part of said first endless path. for decelerating said second gripper means as it moves along the horizontal part of said second endless path and the sheet-like member ongaged by the second gripper means from a relatively high speed at which said main conveyor means transported the sheet-like member to a relatively low speed at which the sheet-like member is released by said second gripper means at the receiving station, and for subsequently accelerating said second gripper means to the relatively high speed at which said main conveyor means transported the sheet-like member to enable said second gripper means to engage a next succeeding sheet-like member, vacuum means for applying suction to a trailing end portion of the sheet-like member as the speed of the sheet-like member is being reduced by said slowdown conveyor means to thereby retard forward movement of the trailing end portion of the sheet-like member and minimize buckling of the sheet-like member, said vacuum means including a surface portion which engages the sheet-like member and is moved in the same direction as the sheet-like member to thereby minimize the possibility of rupturing connections between the portions of the sheet-like member due to the effect of said vacuum means, and means for rendering said vacuum means ineffective for applying suction to the trailing end portion of the sheet-like member while the leading end portion of the sheet-like member is moving through the pickup station.

23. An assembly for sequentially transporting a series of sheet-like members from a pickup station to a pile of sheet-like members at a receiving station, said assembly comprising main conveyor means for transporting each of the sheet-like members in turn to a transfer station disposed over the pile of sheet-like members, said main conveyor means including a first plurality of gripper assemblies and first flexible connector means for moving said first plurality of gripper assemblies along a first endless path which is at least partially disposed over the pile of sheet-like members, and slowdown conveyor means for receiving each of the sheet-like members in turn from said main conveyor means at the transfer station over the pile of sheet-like members, for reducing the speed of movement of each of the sheet-like members in turn, and for releasing each of the sheet-like members in turn at the receiving station, said main conveyor means being operable to move a leading end portion of each of the sheet-like members in turn from a position rearwardly of a trailing end portion of a next .preceding sheet-like member to a position overlapping the trailing end portion of the next preceding sheet-like member while the next preceding sheet-like member is moving forwardly under the influence of said slowdown conveyor means, said slowdown conveyor means including a second plurality of gripper assemblies and second flexible connector means for moving said second plurality of gripper assemblies along a second endless path which is at least partially disposed over the pile of sheet-like members.

24. An assembly as set forth in claim 23 further including means for urging the trailing end portion of said next preceding sheet-like member downwardly to enable said main conveyor means to move the leading edge portion of a sheet-like member into an overlapping relationship with said next preceding sheet-like member.

25. An assembly as set forth in claim 24 wherein said means for urging the trailing end portion of said next preceding sheet-like member downwardly includes vacuum means for applying suction to the trailing end portion of said next preceding sheet-like member.

26. An assembly as set forth in claim 23 further including vacuum means for applying suction to a trailing end portion of a sheet-like member as the speed of the sheet-like member is being reduced by said slowdown conveyor means, and means for rendering said vacuum means ineffective for applying suction to the trailing end portion of the sheet-like member while the sheetlike member is moving under the influence of said main conveyor means.

27. An apparatus as set forth in claim 23 further including means for supporting said main conveyor means and said slowdown conveyor means in positions which at the transfer station are above a path of movement of a sheet-like member through the transfer station.

28. A method of transporting a sheet-like member to a receiving station where the sheet-like member is positioned on a pile of sheet-like members by engagement of a leading end portion of the sheet-like member with a stop member, said method comprising the steps of engaging the leading end portion of the sheet-like member with a main conveyor assembly, transporting the sheet-like member to a transfer station along a path which extends horizontally above the pile by operating the main conveyor assembly at a high speed, engaging the leading end portion of the sheet-like member at the transfer station directly above the pile with a slowdown conveyor assembly which is operating at the same speed as the main conveyor assembly, disengaging the sheet-like member from the main conveyor assembly, reducing the speed of the sheet-like member as the leading end portion of the sheet-like member moves along the horizontal path by reducing the speed of operation of the slowdown conveyor assembly, and disengaging the sheet-like member from the slowdown conveyor assembly at the receiving station while the leading end portion of the sheet-like member is traveling at the reduced speed along the horizontal path to thereby enable the sheet-like member to move into engagement with the stop member at a relatively low speed to minimize the possibility of damage to the sheet-like member.

29. A method as set forth in claim 28 wherein said step of reducing the speed of the sheet-like member is performed by operating a differential gear assembly to reduce the speed of rotation of an output member which is drivingly connected to the slowdown conveyor assembly relative to the speed of rotation of an input member which drivingly connects a substantially constant speed source of power with the differential gear assembly.

30. A method as set forth in claim 28 further including the method step of retarding movement of a trailing end portion of the sheet-like member during said step of reducing the speed of the sheet-like member to thereby minimize any tendency of the sheet-like member to buckle.

31. A method as set forth in claim 30 wherein said step of retarding movement of a trailing end portion of the sheet-like member includes the step of applying suction to the trailing end portion of the sheet-like member.

32. A method as set forth in claim 28 wherein said step of disengaging the sheet-like member from the main conveyor assembly is performed after the sheetlike member has been engaged by the slowdown conveyor assembly and while the leading end of the sheetlike member is moving along the horizontal path.

33. In a method of stacking flat sheets in a pile with the sides thereof vertically aligned, the steps of feeding sheets horizontally in a sheet path at a constant speed with a space between adjacent sheets, advancing the sheets in said path over said pile, gripping the leading edge of a first sheet after it has passed forward of the rear edge of said pile, decelerating the first sheet while a second sheet continues movement in said sheet path at the aforesaid constant speed, moving the trailing edge of the decelerating first sheet to a position below the sheet path, allowing the leading edge of the second sheet to advance above and past the trailing edge of the decelerating first sheet, releasing the first sheet before arrival of its leading edge at the corresponding lead edge of the pile to allow settling of the first sheet on top of the pile, and grasping the leading edge of the second sheet while moving at constant speed and decelerating said second sheet before depositing it on the delivery pile.

34. The method of claim 33 including the steps of severing each sheet while moving at said constant speed into a plurality of sections held together by weak tabs.

35. The method of claim 33 including the steps of applying vacuum to the rear underside of each decelerating sheet to assist said deceleration.

36. The method of claim 35 including the additional steps of deactivating the application of vacuum after vacuum has been applied to the trailing edge of the first sheet, and applying vacuum to the underside of the second sheet as its leading edge is decelerated.

37. The method of claim 33 including the steps of supporting sheets while traveling at both said constant and decelerating speeds by grasping them along their leading edges from above and below. 

1. A sheet slowdown mechanism for reducing the speed of a moving sheet-like member before it is deposited on a pile of sheet-like members at a receiving station where the sheet-like member is positioned on the pile by engagement of its leading end portion with a stop member, said mechanism comprising main conveyor means for transporting the sheet-like member to a transfer station which is located directly above the pile while grippingly engaging the leading end portion of the sheet-like member and for releasing the sheet-like member at the transfer station, said main conveyor means including first gripper means for engaging the leading end portion of the sheet-like member and first chain means for moving said first gripper means along a first endless path, and slowdown conveyor means for grippingly engaging the leading end portion of the sheet-like member over the pile at the transfer station while the sheet-like member is being moved under the influence of said main conveyor means, for reducing the speed of movement of the sheet-like member while transporting the sheet-like member away from the transfer station, and for releasing the leading end portion of the sheet-like member after reducing its speed to a speed substantially below the speed at which the sheet-like member is transported by said main conveyor means to thereby minimize the possibility of damage to the sheetlike member when it engages the stop member, said slowdown conveyor means including second gripper means for engaging the leading end portion of the sheet-like member at the transfer station and second chain means for moving said second gripper means along a second endless path.
 2. A sheet slowdown mechanism as set forth in claim 1 wherein said first chain means includes first and second parallel runs of chain, and said slowdown conveyor means includes means for supporting said second gripper means for movement between said fIrst and second runs of said first chain means.
 3. A sheet slowdown mechanism as set forth in claim 1 further including means for retarding forward movement of a trailing end portion of the sheet-like member as said slowdown conveyor means reduces the speed of movement of the sheet-like member and means for rendering said means for retarding forward movement of the sheet-like member ineffective at times other than when the speed of the sheet-like member is being reduced by said slowdown conveyor means.
 4. A sheet slowdown mechanism as set forth in claim 1 wherein said first gripper means includes clamp means for clampingly engaging opposite sides of the leading end portion of the sheet-like member and drive means for moving said clamp means along a horizontal path extending over the pile, and said second gripper means includes clamp means for clampingly engaging opposite sides of the leading end portion of the sheet-like member, drive means for moving said slowdown conveyor clamp means along the horizontal path at a speed which is equal to the speed at which the sheet-like member is moved by said main conveyor means when said slowdown conveyor clamp means is moving through the transfer station to thereby facilitate engagement of the leading edge portion of the sheet-like member while it is being moved by said main conveyor means, for reducing the speed of said slowdown conveyor clamp means while the slowdown conveyor clamp means is being moved along the horizontal path after the leading end portion of the sheet-like member has been engaged by said slowdown conveyor clamp means and said main conveyor means has released the leading end of the sheet-like member, and for accelerating the clamp means after the leading end portion of the sheet-like member has been released by said clamp means at the receiving station to thereby bring the speed of the clamp means back up to at least the speed at which the sheet-like member is transported by said main conveyor means.
 5. A sheet slowdown mechanism as set forth in claim 4 wherein said drive means includes differential gear means for driving said slowdown conveyor means, said differential gear means including an input member operatively connected to a substantially constant speed source of power and an output member operatively connected to said slowdown conveyor means, said drive means further including means for operating said differential gear means to reduce the speed of said output member relative to the speed of said input member to thereby effect the aforesaid reduction in the speed of said clamp means for for operating said differential gear means to accelerate said output member relative to said input member to thereby effect the aforesaid acceleration of said clamp means.
 6. A sheet slowdown mechanism as set forth in claim 1 wherein said first chain means includes first and second horizontal runs of chain disposed above the pile of sheets and extending from at least a trailing end portion of the pile of sheets to a leading end portion of the pile of sheets.
 7. A sheet slowdown mechanism as set forth in claim 6 wherein said first gripper means includes a post portion and a finger portion for engaging the sheet-like member with an operating surface and pressing the sheet-like member against an operating surface of said post portion, and said second gripper means includes a post portion for engaging the sheet-like member and a finger portion for engaging the sheet-like member with an operating surface and pressing the sheet-like member against an operating surface of said post portion of said second gripper means, each of said operating surfaces of said second gripper means being substantially coplanar with one of said operating surfaces of said first gripper means when said second gripper means is initially brought into engagement with said sheet-like member at said transfer station to thereby minimize distortion of the sheet-like member.
 8. A sheet slowdown mechanism as set forth in claim 6 wherein said slowdOwn conveyor means includes means for supporting said second chain means and said second gripper means for movement along a portion of the second path which extends between said first and second horizontal runs of chain.
 9. A sheet slowdown mechanism as set forth in claim 1 further including vacuum means for applying suction to a trailing end portion of the sheet-like member as the speed of the sheet-like member is being reduced by said slowdown conveyor means to thereby tend to minimize buckling of the sheet-like member as its speed is reduced by said slowdown conveyor means.
 10. An assembly comprising main conveyor means for transporting a sheet-like member to a transfer station, said main conveyor means including first clamp means operable from an open condition to a closed condition clampingly engaging the sheet-like member, first drive means for moving said first clamp means along a first endless path having a straight portion which extends through the transfer station, and first actuator means for operating said first clamp means from the closed condition to the open condition as said first clamp means moves along said straight portion of the first path, and slowdown conveyor means for receiving the sheet-like member from said main conveyor means at the transfer station and for reducing the speed of movement of the sheet-like member to a speed substantially below the speed at which the sheet-like member is transported by said main conveyor means and for the releasing the sheet-like member at a receiving station, said slowdown conveyor means including second clamp means operable from an open condition to a closed condition clampingly engaging the sheet-like member as it is moving through the transfer station along the straight portion of the first endless path under the influence of said main conveyor means, second drive means for moving said second clamp means along a second endless path having a straight portion which extends through the transfer station and is transversely adjacent and parallel to said straight portion of the first endless path which extends through the transfer station to thereby facilitate engagement of the sheet-like member by said second clamp means while the sheet-like member is being moved through said transfer station by said main conveyor means, and second actuator means for operating said second clamp means from the open condition to the closed condition as said second clamp means moves along said straight portion of said second path.
 11. An assembly as set forth in claim 10 wherein said second drive means includes an input member operatively connected with a source of power which drives said input member at a substantially constant speed, a rotatable output member drivingly connected with said second clamp means, and means for rotating said output member at a first rate so that said second clamp means is moved forwardly by said second drive means along said straight portion of the second endless path at a speed which is substantially the same as the speed at which said first clamp means is moved through said transfer station by said first drive means, for reducing the rate of rotation of said output member to a second rate which is substantially less than said first rate of rotation to thereby reduce the speed of forward movement of said second clamp means along said straight portion of said second endless path and the speed of movement of the sheet-like member before the sheet-like member is released at the receiving station, and for increasing the rate of rotation of said output member from said second rate to said first rate before said second clamp means engages another sheet-like member at the transfer station.
 12. An assembly as set forth in claim 11 wherein said means for rotating said output member includes differential gear means for enabling relative rotation to occur between said output member and said input member.
 13. An assembly as set forth in claim 12 wherein said means for rotating said output member fUrther includes cam means for actuating said differential gear means to effect relative rotation between said output member and said input member.
 14. An assembly as set forth in claim 11 wherein said straight portions of said first and second endless paths extend beyond a leading end portion of the pile.
 15. An assembly as set forth in claim 10 wherein said first clamp means includes a plurality of main gripper assemblies, said first drive means includes first flexible connector means for interconnecting and moving said main gripper assemblies along the first endless path, said second clamp means includes a plurality of slowdown gripper assemblies, and said second drive means includes second flexible connector means for interconnecting and moving said slowdown gripper assemblies along the second endless path which is circumscribed by the first endless path along which said main gripper assemblies are moved by said first drive means.
 16. An assembly as set forth in claim 10, further including vacuum means for applying suction to a trailing end portion of the sheet-like member as the speed of the sheet-like member is being reduced by said slowdown conveyor means to thereby retard forward movement of the trailing end portion of the sheet-like member.
 17. An assembly as set forth in claim 16 further including means for rendering said vacuum means ineffective for applying suction to the trailing end portion of the sheet-like member while the sheet-like member is moving under the influence of said main conveyor means.
 18. An assembly for transporting a sheet-like member having a plurality of interconnected portions to a receiving station whereat the sheet-like member is positioned in a predetermined orientation by engagement of a leading end portion of the sheet-like member with a stop member, said assembly comprising main conveyor means for transporting the sheet-like member from a pickup station to a transfer station and releasing the sheet-like member at the transfer station, said main conveyor means including first gripper means for engaging a leading end portion of a sheet-like member and first drive means for moving said first gripper means along a first endless path a horizontal part of which extends through said transfer station, and slowdown conveyor means for continuously reducing the speed of the sheet-like member to a speed substantially below the speed at which the sheet-like member is transported by said main conveyor means after the leading end portion of the sheet-like member has moved through the pick-up station and releasing the sheet-like member at the receiving station while it is traveling at such a speed that the leading end portion engages the stop member to arrest forward movement of the sheet-like member without rupturing the connections between the portions of the sheet-like member, said slowdown conveyor means including second gripper means for engaging the leading end portion of the sheet-like member as it moves along the horizontal part of said first endless path at the transfer station while the sheet-like member is moving forward under the influence of the main conveyor means and second drive means for moving said second gripper means along a second endless path a horizontal part of which extends adjacent and parallel to said horizontal part of said first endless path, for decelerating said second gripper means as it moves along the horizontal part of said second endless path and the sheet-like member engaged by the second gripper means from a relatively high speed at which said main conveyor means transported the sheet-like member to a relatively low speed at which the sheet-like member is released by said second gripper means at the receiving station, and for subsequently accelerating said second gripper means to the relatively high speed at which said main conveyor means transported the sheet-like member to enable said second gripper means to engage a next succeeding sheet-like member, said first gripper means including a plUrality of main gripper assemblies, said first drive means including first flexible connector means for interconnecting and moving said main gripper assemblies along the endless path, said second gripper means including a plurality of slowdown gripper assemblies, and said second drive means including second flexible connector means for interconnecting and moving said slowdown gripper assemblies along an endless path which is circumscribed by the endless path along which said main gripper assemblies are moved by said first drive means.
 19. An assembly as set forth in claim 18 further including means for retarding forward movement of a trailing end portion of the sheet-like member while the speed of the sheet-like member is being reduced by said slowdown conveyor means.
 20. An assembly as set forth in claim 18 wherein said second drive means includes differential gear means for drivingly connecting a substantially constant speed source of power with said slowdown conveyor means and means for actuating said differential gear means to effect the deceleration and acceleration of said second gripper means.
 21. An assembly as set forth in claim 18 further including vacuum means for applying suction to a trailing end portion of the sheet-like member as the speed of the sheet-like member is being reduced by said slowdown conveyor means to thereby retard forward movement of the trailing end portion of the sheet-like member and minimize buckling of the sheet-like member, said vacuum means including a surface portion which engages the sheet-like member and is moved in the same direction as the sheet-like member to thereby minimize the possibility of rupturing connections between the portions of the sheet-like member due to the effect of said vacuum means.
 22. An assembly for transporting a sheet-like member having a plurality of interconnected portions to a receiving station whereat the sheet-like member is positioned in a predetermined orientation by engagement of a leading end portion of the sheet-like member with a stop member, said assembly comprising main conveyor means for transporting the sheet-like member from a pickup station to a transfer station and releasing the sheet-like member at the transfer station, said main conveyor means including first gripper means for engaging a leading end portion of a sheet-like member and first drive means for moving said first gripper means along a first endless path a horizontal part of which extends through said transfer station, slowdown conveyor means for continuously reducing the speed of the sheet-like member to a speed substantially below the speed at which the sheet-like member is transported by said main conveyor means after the leading end portion of the sheet-like member has moved through the pick-up station and releasing the sheet-like member at the receiving station while it is traveling at such a speed that the leading end portion engages the stop member to arrest forward movement of the sheet-like member without rupturing the connections between the portions of the sheet-like member, said slowdown conveyor means including second gripper means for engaging the leading end portion of the sheet-like member as it moves along the horizontal part of said first endless path at the transfer station while the sheet-like member is moving forward under the influence of the main conveyor means and second drive means for moving said second gripper means along a second endless path a horizontal part of which extends adjacent and parallel to said horizontal part of said first endless path, for decelerating said second gripper means as it moves along the horizontal part of said second endless path and the sheet-like member engaged by the second gripper means from a relatively high speed at which said main conveyor means transported the sheet-like member to a relatively low speed at which the sheet-like member is released by said second gripper means at the receiving station, and for subsequently accelerating said second gripper meanS to the relatively high speed at which said main conveyor means transported the sheet-like member to enable said second gripper means to engage a next succeeding sheet-like member, vacuum means for applying suction to a trailing end portion of the sheet-like member as the speed of the sheet-like member is being reduced by said slowdown conveyor means to thereby retard forward movement of the trailing end portion of the sheet-like member and minimize buckling of the sheet-like member, said vacuum means including a surface portion which engages the sheet-like member and is moved in the same direction as the sheet-like member to thereby minimize the possibility of rupturing connections between the portions of the sheet-like member due to the effect of said vacuum means, and means for rendering said vacuum means ineffective for applying suction to the trailing end portion of the sheet-like member while the leading end portion of the sheet-like member is moving through the pickup station.
 23. An assembly for sequentially transporting a series of sheet-like members from a pickup station to a pile of sheet-like members at a receiving station, said assembly comprising main conveyor means for transporting each of the sheet-like members in turn to a transfer station disposed over the pile of sheet-like members, said main conveyor means including a first plurality of gripper assemblies and first flexible connector means for moving said first plurality of gripper assemblies along a first endless path which is at least partially disposed over the pile of sheet-like members, and slowdown conveyor means for receiving each of the sheet-like members in turn from said main conveyor means at the transfer station over the pile of sheet-like members, for reducing the speed of movement of each of the sheet-like members in turn, and for releasing each of the sheet-like members in turn at the receiving station, said main conveyor means being operable to move a leading end portion of each of the sheet-like members in turn from a position rearwardly of a trailing end portion of a next preceding sheet-like member to a position overlapping the trailing end portion of the next preceding sheet-like member while the next preceding sheet-like member is moving forwardly under the influence of said slowdown conveyor means, said slowdown conveyor means including a second plurality of gripper assemblies and second flexible connector means for moving said second plurality of gripper assemblies along a second endless path which is at least partially disposed over the pile of sheet-like members.
 24. An assembly as set forth in claim 23 further including means for urging the trailing end portion of said next preceding sheet-like member downwardly to enable said main conveyor means to move the leading edge portion of a sheet-like member into an overlapping relationship with said next preceding sheet-like member.
 25. An assembly as set forth in claim 24 wherein said means for urging the trailing end portion of said next preceding sheet-like member downwardly includes vacuum means for applying suction to the trailing end portion of said next preceding sheet-like member.
 26. An assembly as set forth in claim 23 further including vacuum means for applying suction to a trailing end portion of a sheet-like member as the speed of the sheet-like member is being reduced by said slowdown conveyor means, and means for rendering said vacuum means ineffective for applying suction to the trailing end portion of the sheet-like member while the sheet-like member is moving under the influence of said main conveyor means.
 27. An apparatus as set forth in claim 23 further including means for supporting said main conveyor means and said slowdown conveyor means in positions which at the transfer station are above a path of movement of a sheet-like member through the transfer station.
 28. A method of transporting a sheet-like member to a receiving station where the sheet-like member is positioned on a pile of sheet-liKe members by engagement of a leading end portion of the sheet-like member with a stop member, said method comprising the steps of engaging the leading end portion of the sheet-like member with a main conveyor assembly, transporting the sheet-like member to a transfer station along a path which extends horizontally above the pile by operating the main conveyor assembly at a high speed, engaging the leading end portion of the sheet-like member at the transfer station directly above the pile with a slowdown conveyor assembly which is operating at the same speed as the main conveyor assembly, disengaging the sheet-like member from the main conveyor assembly, reducing the speed of the sheet-like member as the leading end portion of the sheet-like member moves along the horizontal path by reducing the speed of operation of the slowdown conveyor assembly, and disengaging the sheet-like member from the slowdown conveyor assembly at the receiving station while the leading end portion of the sheet-like member is traveling at the reduced speed along the horizontal path to thereby enable the sheet-like member to move into engagement with the stop member at a relatively low speed to minimize the possibility of damage to the sheet-like member.
 29. A method as set forth in claim 28 wherein said step of reducing the speed of the sheet-like member is performed by operating a differential gear assembly to reduce the speed of rotation of an output member which is drivingly connected to the slowdown conveyor assembly relative to the speed of rotation of an input member which drivingly connects a substantially constant speed source of power with the differential gear assembly.
 30. A method as set forth in claim 28 further including the method step of retarding movement of a trailing end portion of the sheet-like member during said step of reducing the speed of the sheet-like member to thereby minimize any tendency of the sheet-like member to buckle.
 31. A method as set forth in claim 30 wherein said step of retarding movement of a trailing end portion of the sheet-like member includes the step of applying suction to the trailing end portion of the sheet-like member.
 32. A method as set forth in claim 28 wherein said step of disengaging the sheet-like member from the main conveyor assembly is performed after the sheet-like member has been engaged by the slowdown conveyor assembly and while the leading end of the sheet-like member is moving along the horizontal path.
 33. In a method of stacking flat sheets in a pile with the sides thereof vertically aligned, the steps of feeding sheets horizontally in a sheet path at a constant speed with a space between adjacent sheets, advancing the sheets in said path over said pile, gripping the leading edge of a first sheet after it has passed forward of the rear edge of said pile, decelerating the first sheet while a second sheet continues movement in said sheet path at the aforesaid constant speed, moving the trailing edge of the decelerating first sheet to a position below the sheet path, allowing the leading edge of the second sheet to advance above and past the trailing edge of the decelerating first sheet, releasing the first sheet before arrival of its leading edge at the corresponding lead edge of the pile to allow settling of the first sheet on top of the pile, and grasping the leading edge of the second sheet while moving at constant speed and decelerating said second sheet before depositing it on the delivery pile.
 34. The method of claim 33 including the steps of severing each sheet while moving at said constant speed into a plurality of sections held together by weak tabs.
 35. The method of claim 33 including the steps of applying vacuum to the rear underside of each decelerating sheet to assist said deceleration.
 36. The method of claim 35 including the additional steps of deactivating the application of vacuum after vacuum has been applied to the trailing edge of the first sheet, and applying vacuum to the underside of The second sheet as its leading edge is decelerated.
 37. The method of claim 33 including the steps of supporting sheets while traveling at both said constant and decelerating speeds by grasping them along their leading edges from above and below. 